This application claims priority upon German application 199 18 823.8 filed Apr. 26, 1999, which application is incorporated herein by reference.
The invention relates to a lid stay to hold open a lid or a flap on a piece of furniture. The lid, as a rule, is vertically arranged and pivotably attached to the piece of furniture. The lid is pivotably attached to the furniture piece by hinges, for example, at the upper edge of the lid. Therefore, the lid can be folded from the vertically closed position upwards into an open position. Accordingly, the lid is essentially arranged horizontally or inclined.
DE 26 53 106 C2 discloses a flap holder for an upwards or downwards opening flap. The flap holder has two arms that are pivotably connected to each other at one end around a swivel axis. The other ends of the arms are provided with connection means to connect the arms to a fitting. One of the fittings serves to fix the arm to a body of the furniture piece, which is closable by the flap and the other fitting serves to fix the arm to the flap. One of the arms has a cam contour in the area of the swivel axis. The cam contour has cam faces extending parallel to the swivel axis. The other arm supports a slider, which is movable in the longitudinal direction of the arm. This slider is preloaded by a spring in a direction towards the swivel axis. The spring is arranged within a square opening of the arm. The slider has a hole which enables the slider to be movably mounted on the arm. The hole encloses the arm and the spring. A front face faces the swivel axis. The front face forms an abutment face for the cam contour and acts as a sliding face. The front face extends transversely to the adjustment direction of the slider. A groove follows the flat sliding face. One of the cam faces collaborates with the abutment face of the slider in an open position of the arms. The arms are supported. In the closed position of the flap, the one cam face collaborates with a face of the groove. Accordingly, the flap is pulled into the closed position. The disadvantage of this embodiment is, that the flap is only held in specific positions when the cam face collaborates with the sliding face. In all the other positions, the flap is not held and falls downwards.
EP 0 646 690 A1 discloses a stay, which is preferentially used in roof boxes for vehicles. The stay holds the lid of the roof box in an open position. The stay has two arms. The arms are pivotably connected to each other around a swivel axis. A spring acts between the two arms. The spring moves the arms to a position where the lid of the roof box is in the open position. Accordingly, the spring supports the lid while opening the lid of the roof box. However, as the spring force changes dependent on the position of the arms, with respect to one another, the lid of the roof box is only held in a position, as long as the torque around the swivel axis caused by the spring force balances the torque caused by the mass force of the lid of the roof box. In positions of the arms which differ from the above, the lid of the roof box closes or is forced in the direction towards the open position.
An object of the present invention is to provide a lid stay for upwards opening lids, which enables an easy moving of the lid which holds the lid in every desired position over the swivel area of the lid.
Accordingly, the lid stay of the present invention includes a first arm and second arms. The second arm is pivotably connected to the first arm around a swivel axis. The second arm is movable between an open position and a closed position.
A friction member is effective between the first arm and the second arm. A spring urges the second arm in a direction to the open position or in a direction to the closed position. The spring acts upon the friction member to influence the frictional force.
Over the swivel area of the lid the torque around the swivel axis of the lid stay changes continuously due to the mass force of the lid and due to the spring force of the lid stay. Additionally, the friction member forms a torque caused by frictional forces. These frictional forces must additionally be overcome to the torque caused by the mass force while opening the lid. The frictional forces and the torque caused by the spring force have to be overcome while closing the lid. Even in swivel positions of the lid, where the torque caused by the mass force and the torque caused by the spring force are not balanced out, the lid is still held in its position, as a torque caused by the frictional forces must additionally be overcome.
In order to open the lid, not all the total mass force of the lid has to be overcome. Since the spring force supportingly acts on the lid stay, it helps in opening the lid. Only the torque caused by the frictional force and the difference between the torque caused by the spring force and the torque caused by the mass force have to be overcome in order to open the lid. The same is applicable for closing the lid, as the mass force works supportively against the positioning force of the lid stay.
The torque to be overcome and caused by the frictional forces is always adapted to the actual swivel position of the lid. At swivel positions of the lid in the vicinity of the open position, the spring force and the torque resulting from that position is smallest. In the case where the spring force is sufficient to move the lid into the open position, the frictional forces guarantee that the lid is held in its swivel position. In the case where the torque caused by the spring force is smaller than the torque caused by the mass force, the torque to be overcome, caused by the frictional forces, acts in reverse and keeps the lid in the respective swivel position as well preventing the lid from falling downwards. In swivel positions in the vicinity of the open position, the spring force is smallest and results in small frictional forces. These small frictional forces are sufficient for small differences between the torque caused by the spring force and the torque caused by the mass force. If the lid is moved from the open position to the closed position, due to the lever ratios, the spring forces and thus the opening torque of the lid stay increase and the torque caused by the mass force of the lid decreases. As the frictional forces increase proportional to the spring forces, the lid is prevented from opening the positioning force of the lid stay. The frictional forces are therefore always adapted to the respective force ratios and hold the lid in any position.
A compact lid stay design is provided, which is movably supported relative to a first arm and connected to a second arm. An adjustment slider is kept in frictional contact with the first arm. The slider represents the friction member. The springs are represented by compression springs, which act upon the second arm, via the adjustment slider.
Preferably, the first arm includes a housing. The adjustment slider is movably supported in the housing. Likewise, the spring mechanism is arranged in the housing. The adjustment slider is in frictional contact with the inner faces of the housing. Preferably, the spring mechanism is in the form of compression springs. The compression springs are arranged within the adjustment slider. The adjustment slider and the spring mechanism are protected within the housing. Accordingly, the springs and the adjustment slider are not exposed to exterior influences. Thus, this reduces the chance that the spring mechanism or the adjustment slider will be damaged.
The adjustment slider includes a first slider part and a second slider part. The first and second slider parts are respectively in frictional contact with one inner face of the housing. The spring mechanism is supported against the second slider part. The first slider part is connected to the second arm. The first slider part abuts the second slider part, via an adjustment face. The adjustment face abuts an abutment face of the second slider part. The adjustment face and the abutment face are arranged at an angle to the adjustment direction of the adjustment slider. Therefore, the two slider parts are forced apart with increasing spring force. Thus, the outer faces of the slider parts are pressed stronger against the inner faces of the housing.
In a preferred embodiment, the second arm includes a lever. The lever eccentrically connects to the swivel axis. The axis of rotation extends parallel to the swivel axis. The lever is rigidly connected to the adjustment slider in the adjustment direction of the adjustment slider. Also, the lever is movably connected to the adjustment slider transverse to the adjustment direction of the adjustment slider.
From the following detailed description, taken in conjunction with the accompanying drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.